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Screening of tea clones for inhibition of PhIP mutagenicity
Z Apostolides1, J H Weisburger
1Department of Biochemistry, University of Pretoria, South Africa.
Abstract:
Standard black and green tea extracts have been known to inhibit mutagenicity caused by PhIP, in the Salmonella typhimurium TA98 assay containing S9 fraction from the liver of rats induced with alpha-naphthoflavone and phenobarbital. Breeding and selection programs for high yielding tea clones have successfully increased yields in many tea producing areas. Six clonal teas and three seedling teas were obtained from a tea producing area in Southern Africa. Standard black and green teas were used as controls. Dose-dependent inhibition of the bacterial mutagenicity elicited by two concentrations of PhIP was found in the extracts of all the teas tested. This indicates that the clonal teas have not lost their anti-mutagenic properties. Small differences were found amongst the clonal teas in their ability to inhibit mutagenicity. This indicates that it may be possible to enhance this trait in future breeding and selection programs.
Insights
Tea extracts, including clonal varieties, effectively inhibit PhIP-induced mutagenicity in bacterial assays. This confirms that anti-mutagenic properties are retained in high-yielding tea clones, suggesting potential for enhancement through breeding programs.
Area of Science:
- Food Science
- Toxicology
- Plant Breeding
Background:
- Standard black and green tea extracts demonstrate anti-mutagenic properties against PhIP (2-amino-1,2-dimethyl-6-phenylimidazo[4,5-b]pyridine) in bacterial mutagenicity assays.
- Tea breeding programs have focused on increasing yield, raising questions about the retention of other beneficial compounds like anti-mutagens.
Purpose of the Study:
- To evaluate the anti-mutagenic potential of clonal tea extracts against PhIP-induced mutagenicity.
- To determine if high-yielding tea clones retain the anti-mutagenic properties found in standard teas.
- To explore the possibility of enhancing anti-mutagenic traits in tea through breeding.
Main Methods:
- Six clonal teas and three seedling teas from Southern Africa were tested, alongside standard black and green teas as controls.
- The Salmonella typhimurium TA98 assay, utilizing a liver S9 fraction, was employed to assess mutagenicity inhibition.
- Dose-dependent inhibition was measured against two concentrations of PhIP.
Main Results:
- All tested tea extracts, including clonal varieties, exhibited dose-dependent inhibition of PhIP-induced bacterial mutagenicity.
- The anti-mutagenic properties were present in the clonal teas, indicating no loss of this trait due to breeding for yield.
- Minor variations in anti-mutagenic efficacy were observed among the different clonal teas.
Conclusions:
- Clonal teas possess significant anti-mutagenic properties, comparable to standard black and green teas.
- Breeding for high yield in tea has not compromised its inherent anti-mutagenic capabilities.
- There is potential to further enhance the anti-mutagenic trait in tea through targeted breeding and selection strategies.